Ceriantipatharia is a deprecated

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

coral Corals are colonial marine invertebrates within the subphylum Anthozoa of the phylum Cnidaria. They typically form compact Colony (biology), colonies of many identical individual polyp (zoology), polyps. Coral species include the important Coral ...

s within the

class Class, Classes, or The Class may refer to: Common uses not otherwise categorized * Class (biology), a taxonomic rank * Class (knowledge representation), a collection of individuals or objects * Class (philosophy), an analytical concept used d ...

Hexacorallia Hexacorallia is a Class (biology), class of Anthozoa comprising approximately 4,300 species of aquatic organisms formed of polyp (zoology), polyps, generally with 6-fold symmetry. It includes all of the stony corals, most of which are Colony (b ...

, although it was initially considered as a subclass in older taxonomies. It was split and it is now replaced by its previous two constituent orders, Ceriantharia (tube-dwelling anemones) and

Antipatharia Antipatharians, also known as black corals or thorn corals, are an order of soft deep-water corals. These corals can be recognized by their jet-black or dark brown chitin skeletons, which are surrounded by their colored polyps (part of coral th ...

(black corals). History and importance as a subclass (now an order) of Hexacorallia Since its definition by Édouard Van Beneden, in 1897, until its deprecation , it remained an important taxon due to its high rank (subclass) in the taxonomy of

Cnidaria Cnidaria ( ) is a phylum under kingdom Animalia containing over 11,000 species of aquatic invertebrates found both in fresh water, freshwater and marine environments (predominantly the latter), including jellyfish, hydroid (zoology), hydroids, ...

, profusely cited in the scientific bibliography and studied by scientists like the

paleontologist Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geolo ...

s Dorothy Hill and John W. Wells, and the

marine biologist Marine biology is the scientific study of the biology of marine life, organisms that inhabit the sea. Given that in biology many phyla, families and genera have some species that live in the sea and others that live on land, marine biology clas ...

J. E. N. Veron, among many others. Van Beneden considered that the similarities in morphology between the larva of the cerianthids (which he called ''cerinula'',

portmanteau In linguistics, a blend—also known as a blend word, lexical blend, or portmanteau—is a word formed by combining the meanings, and parts of the sounds, of two or more words together.

of ''ceri''anthid and pla''nula'') and the antipatharian polyp were the main reason for separating the orders Ceriantharia and Antipatharia from the other Hexacorallia orders, and group them as a distinct subclass, Ceriantipatharia. Unlike van Beneden, in volume I (''Porifera through Ctenophora'') of her six-volume treatise ''The Invertebrates'' (1940), Hyman did not group together the orders Ceriantharia and Antipatharia. Nor was Ceriantipatharia mentioned, even though she cited van Beneden in the bibliography for each of those orders (ps.660-661). The reason could be that, as she states in the preface, she followed mainly the German school of zoologists. Her treatise was based on Bronn's ''Klassen und Ordnungen des Tierreichs'' (1862), edited before van Beneden's definition of Ceriantipatharia, and on Kükenthal- Krumbach's ''Handbuch der Zoologie'' (1923), that she considered "the most extensive modern treatise on zoology" (p.31). In the latter treatise, van Beneden is mentioned but not in connection with Ceriantipatharia, which is also not mentioned anywhere by the German authors. In 1956, Wells and Hill, following van Beneden, added two more criteria to group the orders Ceriantharia and Antipatharia within the subclass Ceriantipatharia: Besides the structure of the larva ''cerinula'' already described in 1897, they added that there were also similarities in the structure of the

mesentery In human anatomy, the mesentery is an Organ (anatomy), organ that attaches the intestines to the posterior abdominal wall, consisting of a double fold of the peritoneum. It helps (among other functions) in storing Adipose tissue, fat and allowi ...

and in the mesenterial musculature. In 1995, an analysis of the

ribosomal DNA The ribosomal DNA (rDNA) consists of a group of ribosomal RNA encoding genes and related regulatory elements, and is widespread in similar configuration in all domains of life. The ribosomal DNA encodes the non-coding ribosomal RNA, integral struc ...

of many species within

Anthozoa Anthozoa is one of the three subphyla of Cnidaria, along with Medusozoa and Endocnidozoa. It includes Sessility (motility), sessile marine invertebrates and invertebrates of brackish water, such as sea anemones, Scleractinia, stony corals, soft c ...

, found that Ceriantipatharia was "the most representative of the ancestral Anthozoa". After an extended and important history as a major subclass of Hexacorallia, in the period 1996-2007 three studies of

molecular phylogenetics Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

determined that Ceriantharia, instead of being a

sister group In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

of Antipatharia, is sister to, or even the basal member of Hexacorallia, and that Antipatharia, on the other hand, should be classified as an order within the class Hexacorallia, sister to the orders

Scleractinia Scleractinia, also called stony corals or hard corals, are marine animals in the phylum Cnidaria that build themselves a hard skeleton. The individual animals are known as polyps and have a cylindrical body crowned by an oral disc in which a mo ...

(stony corals) and

Corallimorpharia Corallimorpharia is an order of marine cnidarians closely related to stony or reef building corals ( Scleractinia). They occur in both temperate and tropical climates, although they are mostly tropical. Temperate forms tend to be very robust, wi ...

(mushroom anemones). Phylogenetic studies ultimately caused Ceriantipatharia to become obsolete and its rank changed to order in modern

taxonomies image:Hierarchical clustering diagram.png, 280px, Generalized scheme of taxonomy Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme o ...

and

phylogenies A phylogenetic tree or phylogeny is a graphical representation which shows the evolutionary history between a set of species or taxa during a specific time.Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA. In o ...

, , despite its significant history in the taxonomic bibliography.

References

{{Taxonbar, from=Q2946654 Cnidarian orders Obsolete animal taxa Hexacorallia